Cow engineered to produce less allergenic milk

In biology, researchers are usually pretty dismissive of experiments that result in only a single sample. When there's (as scientists put it) an "n of one," it's hard to tell whether the results are significant or a random fluke. But, in the case of a paper released on Monday by PNAS, the n happens to be a cow that carries a transgenic construct that knocks down the expression of a gene that encodes one of the major allergens found in milk. And the data that led to the cow makes a compelling case that the development is significant.

The work focuses on the β-lactoglobulin gene (BLG), which encodes a protein that's found in the milk of cows and other ruminants, but isn't produced by humans. That difference may be what makes it one of the major sources of milk allergies, which affect between two and three percent of infants born every year. Getting rid of the gene might make milk a viable option for more people, provided that doing so has no ill effects on the cows.

But deleting the gene is a real challenge. Unlike mice, where genes can be knocked out routinely, the techniques for elimination of genes and cloning of embryos in the cow are quite a bit less advanced. So, the authors turned to a different approach, called RNA interference. This involves designing short pieces of RNA that match sequences in the messenger RNA produced by the BLG gene, which allows them to base pair and form stretches of double-helical RNA. This keeps the messenger RNA from being translated into the BLG protein.

The authors designed 10 different short RNAs that matched sequences in the BLG gene, then tested pairs of them for their ability to block the production of BLG protein in cultured cells. They managed to find a combination that lowered the amount of BLG made into protein by over 90 percent.

But a cultured cell doesn't actually make any milk. So, the authors turned to a convenient research animal: the mouse. Unfortunately, the mouse (like us humans) doesn't make any BLG protein. So, the authors first had to engineer a construct that caused the mice to produce bovine BLG in their mammary glands. Then they had to insert a second construct, one that produced the interfering RNAs. Then they had to get the mice pregnant and milk them. I am not making this up. Their methods section includes the description, "Milk was collected manually into capillary tubes by gentle massage of teats following oxytocin administration."

Again, it all seemed to work nicely. Mice without the interfering RNAs produced lots of BLG, while those with them barely made any. With the general approach validated, the authors turned to the lengthy and expensive process of making a transgenic cow by injecting the DNA that encodes the interfering RNA into cells in culture, then transferring the nucleus of those cells into a cow's egg in order to make a clone. This process is generally inefficient in many mammals, and often produces defective embryos. Only five pregnancies resulted from 57 cloning attempts, and only one produced a live birth. "Unexpectedly, the miRNA 6–4 calf was born without a tail." Oops.

The authors can't tell whether this was a cloning defect, a defect caused by the insertion of the genes for the interfering RNA, or simply a random genetic defect that has nothing to do with the experiments. Breeding should help sort that out.

Fortunately, the calf was a female, and hormone treatment got it to make milk. Which (no doubt much to the authors' relief), did not contain BLG. In fact, the protein levels in the milk remained constant, as other proteins were increased to compensate for the loss of BLG. These include the caseins, which the authors suggest "should provide for increased calcium levels and high cheese yields."

Given the amount of work involved in developing RNA interference for cows, it's somewhat ironic that the same issue of PNAS contains a report on efficient gene knockouts in livestock. Still, that work was done in pigs, so there's no guarantee it will translate smoothly to cattle. And, in the mean time, the New Zealanders behind the transgenic work are undoubtedly attempting to create an entire allergen-free herd.

88 Reader Comments

The work focuses on the β-lactoglobulin gene (BLG), which encodes a protein that's found in the milk of cows and other ruminants, but isn't produced by humans. That difference may be what makes it one of the major sources of milk allergies, which affect between two and three percent of infants born every year. Getting rid of the gene might make milk a viable option for more people, provided that doing so has no ill effects on the cows.

The problem I have with cow's milk (other than the taste which I can't stand) is that basically it's designed to turn little cows into big cows. I'm not a little cow, and I don't want to be a big cow. That being said, I do so love cheese and ice cream, so I'm all for cows that don't make people as sick. Now if only they can find a way to do it to peanuts, so everyone can enjoy PB&J the way we are intended to.

You know 85% of US corn is GMO that has the BT bacteria genetically bred into so that when an insect eats the corn it's stomach explodes.

"Your gut is the frontline of your immune system. When your gut lining is too permeable, or “leaky,” larger bits of food can pass directly into your blood, undigested, triggering food allergies and intolerances. Children are particularly susceptible to the harmful effects of leaky gut and dysbiosis (imbalance in natural flora, which is critical for their health)."

Instead of weening off milk like other animals do humans want to CHANGE THE ANIMAL so that it can still drink it's milk. People are lactose intolerant for a reason.

tend to have a similar thought.

are the 1- 2% of people screaming for cow's milk?

Our 2 year old has a dairy allergy (which he's apparently likely to outgrow). It's a mild inconvenience but really hasn't been that big a deal for us. The biggest downers are ice-cream in the summer and pizza.

There's so many "allergy free" foods out there now (assuming you can find a decent sized grocery store) that it's almost a non-issue. Most of it is totally palatable (well, minus soy cheese which is a horrible abomination that should be cleansed from the earth). I've decided I actually like the taste of soy better myself, but it's more expensive.

Genetically engineering a cow so that these people can (theoretically) drink milk is interesting but it does seem like it's solving the problem using a rather large hammer.

Plus as others have mentioned, it's not entirely surprising that babies of one type of mammal aren't necessarily well suited to drinking the milk of another type of mammal...

You know 85% of US corn is GMO that has the BT bacteria genetically bred into so that when an insect eats the corn it's stomach explodes.

"Your gut is the frontline of your immune system. When your gut lining is too permeable, or “leaky,” larger bits of food can pass directly into your blood, undigested, triggering food allergies and intolerances. Children are particularly susceptible to the harmful effects of leaky gut and dysbiosis (imbalance in natural flora, which is critical for their health)."

Have fun learning. Calling people names is...well you'll figure it out one day I hope!

ss

The science links you posted don't reach the same conclusions you claim they do. The conspiracy theory tinfoil hat links are laughably absurd. I salute your ability to weave the two together without suffering an aneurism, but that's about it.

Instead of weening off milk like other animals do humans want to CHANGE THE ANIMAL so that it can still drink it's milk. People are lactose intolerant for a reason.

tend to have a similar thought.

are the 1- 2% of people screaming for cow's milk?

Our 2 year old has a dairy allergy (which he's apparently likely to outgrow). It's a mild inconvenience but really hasn't been that big a deal for us. The biggest downers are ice-cream in the summer and pizza.

There's so many "allergy free" foods out there now (assuming you can find a decent sized grocery store) that it's almost a non-issue. Most of it is totally palatable (well, minus soy cheese which is a horrible abomination that should be cleansed from the earth). I've decided I actually like the taste of soy better myself, but it's more expensive.

Genetically engineering a cow so that these people can (theoretically) drink milk is interesting but it does seem like it's solving the problem using a rather large hammer.

Plus as others have mentioned, it's not entirely surprising that babies of one type of mammal aren't necessarily well suited to drinking the milk of another type of mammal...

Soy cheese....to paraphrase the great Lewis Black...you can't have soy milk, because there is no Soy Teat.

I've already put my penny in elsewhere on this today, so I'll keep it short.

First, this cow is more a proof of principle, it's not actually going on sale. Second, this technique and TALEN (sequence specific deletion) could be useful for more dangerous allergens such as peanuts. Allergies are on the rise, so lots of people could benefit from targeted allergen deletions.

Then there are cases when ordinary food can be poisonous, e.g. undercooked kidney beans. We could actually reduce poisonings by knocking a gene out, leaving no foreign DNA behind, and therefore nothing for anti-GM activists to complain about. (Ok that last bit was wildly optimistic.)

Lactose intolerant folks can generally drink raw milk, since it is not pasteurized, and the enzymes are still intact to protect the drinker. (Raw vegetables also have this characteristic, which is defeated by over-cooking.) I wonder if people who suffer with milk allergies from pasteurized milk would be similarly affected if they drank raw milk instead.

We have created new materials and new chemicals. We have bred new races. We have engineered new crops, new flowers, new chemicals, new materials. We have diverted and dammed rivers and conquered the atom.

The fact is, the enzymes you're worried about are largely unharmed by the pasteurization process. Meanwhile, the process kills off, you know, typhoid and dysentery and a thousand other diseases that are much, much worse than being lactose intolerant anyway and that you've been sheltered from your whole life. Empty platitudes about how our bodies have bacteria in them therefore killing bacteria in our food is unhealthy are so reductionist and disingenuous as to be laughable--obviously, all bacteria are the same, right? Would you go lick a petri dish carrying a colony of (one of the disease-causing strains of) E.Coli or Gonorrhea? After all, there's plenty of bacteria JUST LIKE THEM in your gut!

Also to the "ha ha what waste of time" folks, Gift makes an excellent point that the lessons learned here extend far beyond inhibiting one protein in one cow. Advances in genetic modification and cloning are advances that have broad-based possibilities.

Speaking of those possibilities and those who abhor them, it always blows my mind how some liberal-leaning americans can full-throatedly mock science-denying "climate skeptics" and identify them with the right, while being in the same party as (or being themselves!) science-denying Anti-GMO activists (and don't get me started on anti-nuclear "environmentalists"). They have the same broad-based denial of scientific consensus, the same "FOLLOW THE MONEY!!111!" conspiracy bent, and the same smug assurance that they personally know the truth, regardless of what signals reality sends them.

@ Volt-aire: It's not always entirely black or white. There are advantages and there are risks and dangers inherent with Science - especially when it leaves the academia for the industrial realm. The (critical and democratic) debate is too often reduced to a dogmatic "us and them" position.

Some research has been focusing on Icelandic cows. They are more or less unchanged from the original stock of Viking-Era cows and are small and do not produce as much milk as other more "modern" types. On the other hand children in Iceland who drink milk are less likely to have allergies.

Anecdotal evidence, ofcourse, but when we lived in the old Soviet Union (And most of Eastern Europe for that matter) allergies, let alone allergies to Milk were unheard of. We drank plenty of raw milk and ate raw milk cheese and even uncooked eggs (in preparation of many desserts) straight fromt the farm with no issues. The French seem to do it even today and they seem to be just fine.In today's world you have allergies to milk, allergies to nuts, allergies to pollen, allergies to so many things. I am sure all the GMO and artificial ingredients in today's food (Especially in the US) have absolutely nothign to do with it, lol.

Is today's world the 1970s? That's when I was born with all the allergies (milk, eggs, peanuts) that you claim only happen now. There was no GMO then.

Maybe it was unheard of because the media you were exposed simply didn't talk about it.

Cow's milk is something that a lot of people cannot tolerate because it's protein profile was not designed for the human body.

Yes, you can modify it...but by fixing one thing, you don't know what else you break.

Are you going to argue against that the number of people effected today being exponentially higher than before?Also regarding media, i dont need media for my evidence, simple observation and chatting around in my immediate circles then (there) and now (here).

Instead of weening off milk like other animals do humans want to CHANGE THE ANIMAL so that it can still drink it's milk. People are lactose intolerant for a reason.

tend to have a similar thought.

are the 1- 2% of people screaming for cow's milk?

As a member of the 1% (CLASS RAGE), I can say that I would love to be able to eat cheesecake.

And, to the poster you quoted: lactose intolerance and a milk allergy are two completely different things. Lactose intolerance involves an inability to digest lactose. A milk allergy is a histamine reaction to components of the milk. If I consume too much dairy, I don't get an upset stomach, I get anaphylaxis.

Is today's world the 1970s? That's when I was born with all the allergies (milk, eggs, peanuts) that you claim only happen now. There was no GMO then.

Maybe it was unheard of because the media you were exposed simply didn't talk about it.

Cow's milk is something that a lot of people cannot tolerate because it's protein profile was not designed for the human body.

Yes, you can modify it...but by fixing one thing, you don't know what else you break.

Are you going to argue against that the number of people effected today being exponentially higher than before?Also regarding media, i dont need media for my evidence, simple observation and chatting around in my immediate circles then (there) and now (here).

Like Autism...it's all a matter of diagnosis.

Allergies have always been around. It was only in the 1970s and 1980s that doctors accurately diagnosed the conditions and enough medical reporting occurred to raise public awareness about conditions like allergies (to various natural foodstuffs) and asthma.

Babies having problems with milk allergies are a relatively new phenomenon with the advent of cow milk based baby formula.

You sound like a clueless idiot though with your "I don't need media for my (anecdotal) evidence" that I will try to posit as proof of a general trend.

Is today's world the 1970s? That's when I was born with all the allergies (milk, eggs, peanuts) that you claim only happen now. There was no GMO then.

Maybe it was unheard of because the media you were exposed simply didn't talk about it.

Cow's milk is something that a lot of people cannot tolerate because it's protein profile was not designed for the human body.

Yes, you can modify it...but by fixing one thing, you don't know what else you break.

Are you going to argue against that the number of people effected today being exponentially higher than before?Also regarding media, i dont need media for my evidence, simple observation and chatting around in my immediate circles then (there) and now (here).

Like Autism...it's all a matter of diagnosis.

Allergies have always been around. It was only in the 1970s and 1980s that doctors accurately diagnosed the conditions and enough medical reporting occurred to raise public awareness about conditions like allergies (to various natural foodstuffs) and asthma.

Babies having problems with milk allergies are a relatively new phenomenon with the advent of cow milk based baby formula.

You sound like a clueless idiot though with your "I don't need media for my (anecdotal) evidence" that I will try to posit as proof of a general trend.

Considering that mass media today is corporate owned, their propaganda (be it about economy recovery or gmo being good for you) is pretty worthless to me. I also happen to have acccess to quite a few people in med profession (at relatively high level of experience) who are all ringing the same bells of alert.Either way feel free to poison yourself. All that matters to me is that GM products are clearly labeled (so i can avoid them) and that there are natural alternatives (i.e. biotech megacorps dont try to use every trick in the legal book to choke small/healthy competition).

Going back to the point about baby formula. The one area I think this advance could play a big role in is in the reduction of infant mortality in developing countries where children who are naturally/genetically predisposed to cow milk allergies could be weaned on GMO baby formula.

Is today's world the 1970s? That's when I was born with all the allergies (milk, eggs, peanuts) that you claim only happen now. There was no GMO then.

Maybe it was unheard of because the media you were exposed simply didn't talk about it.

Cow's milk is something that a lot of people cannot tolerate because it's protein profile was not designed for the human body.

Yes, you can modify it...but by fixing one thing, you don't know what else you break.

Are you going to argue against that the number of people effected today being exponentially higher than before?Also regarding media, i dont need media for my evidence, simple observation and chatting around in my immediate circles then (there) and now (here).

In Soviet Russia, anecdotes evidently ARE the plural form of data. Amazing!

Is today's world the 1970s? That's when I was born with all the allergies (milk, eggs, peanuts) that you claim only happen now. There was no GMO then.

Maybe it was unheard of because the media you were exposed simply didn't talk about it.

Cow's milk is something that a lot of people cannot tolerate because it's protein profile was not designed for the human body.

Yes, you can modify it...but by fixing one thing, you don't know what else you break.

Are you going to argue against that the number of people effected today being exponentially higher than before?Also regarding media, i dont need media for my evidence, simple observation and chatting around in my immediate circles then (there) and now (here).

In Soviet Russia, anecdotes evidently ARE the plural form of data. Amazing!

Facts? Provided by whom? Corporate sponsored media that has been proven (just search around) million of times that they spend billions on disinformation for more $$$?

Dont trust your lying eyes, lol. Btw, more anectotal dataz just for you, not a single child who was raised in Eeastern Europe that i know (talking to many many parents here in NYC, including people in pediatrics) has allergy problems. Every second child who was raised here has allergy to something. Yeah anecdotal dataz, i know, they wont tell you about it on TV.